An example of conventional hologram recording method is disclosed in Patent Document 1. The method disclosed in this document is a technique where a recording beam is applied vertically to a hologram recording medium while a reference beam is applied to the illumination site of the recording beam with its incident angles varied under control of the tilt of a multiplex mirror. The multiplex mirror is supported by a supporting member and is tilted so as to pivot around a point where it is supported. The supporting member is movable in parallel to the hologram recording medium. The incident angle of the reference beam with respect to the hologram recording medium is changed in accordance with the tilt of the multiplex mirror, and then the multiplex mirror is moved in parallel to the hologram recording medium for directing the reference beam to the illumination site. Thus, the interference of the recording beam and the reference beam at the illumination site produces multiplex recording of holograms in accordance with the cross angle between these beams.
Patent Document 1: JP-A-2005-234145
With the above-described conventional hologram recording method, the tilt of the multiplex mirror needs to be controlled for varying the incident angle of the reference beam, and also the parallel movement of the multiplex mirror with respect to the hologram recording medium needs to be controlled for keeping the reference beam directed to the illumination site. Unfavorably, such control tends to be very complicated and difficult.